Abstract
	An important feature of hot workability tests is that they should give information on strength and ductility over the ranges of strain rate, strain and temperature used in practice.  In recent years compression tests have bean developed for obtaining strength, especially at high strain rates. The difficulties with tension, axisymetric compression an torsion and the fact, that the conditions of plane strain are nearly satisfied in many operations (strip and plate rolling), have led to the development of plane strain compression testing. It is now worth noting, that plane-strain compression (with suitable modifications for elevated temperatures) is used in studies to obtain strains at a  constant strain rate.